Activating The Fan With The Scan Tool
Under the Engine Systems test heading, there is a subheading, "Fan solenoid test" that has the selections of on and off. Activating the fan with the scan tool will run the fan at a limited 72% duty cycle, which will help troubleshoot any system problems, and also help with the deaeration procedure.
NOTE:
The engine doesn't need to be running to activate the fan with the scan tool.